1 files changed, 290 insertions, 0 deletions

diff --git a/src/model.c b/src/model.c
new file mode 100644
index 0000000..b256f42
--- /dev/null
+++ b/src/model.c
@@ -0,0 +1,290 @@
+/*
+ * Tuxánci 2 - A first person shooter
+ * Copyright (C) 2007-2011  Tuxánci Development Team
+ * Copyright (C) 2025-2026  Connor Thomson
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <math.h>
+#include <stdlib.h>
+#include <string.h>
+#include "model.h"
+#include "camera.h"
+#include "files.h"
+
+static bool ta_model_push_vertex(ta_model_mesh *mesh, size_t *capacity, const ta_model_vertex *vertex) {
+    if (mesh->vertex_count == *capacity) {
+        size_t next_capacity = *capacity == 0 ? 1024 : *capacity * 2;
+        ta_model_vertex *vertices = realloc(mesh->vertices, next_capacity * sizeof(*vertices));
+        if (!vertices) {
+            return false;
+        }
+        mesh->vertices = vertices;
+        *capacity = next_capacity;
+    }
+    mesh->vertices[mesh->vertex_count++] = *vertex;
+    return true;
+}
+
+bool ta_model_build(const float positions[][3], size_t position_count,
+                   const unsigned int faces[][3], size_t face_count,
+                   ta_model_mesh *mesh) {
+    float *normal_accum = NULL;
+    size_t vertex_capacity = 0;
+    bool success = false;
+
+    memset(mesh, 0, sizeof(*mesh));
+    if (position_count == 0 || face_count == 0) {
+        return false;
+    }
+
+    for (size_t index = 0; index < face_count; index++) {
+        for (int corner = 0; corner < 3; corner++) {
+            if (faces[index][corner] >= position_count) {
+                return false;
+            }
+        }
+    }
+
+    normal_accum = calloc(position_count * 3, sizeof(*normal_accum));
+    if (!normal_accum) {
+        goto done;
+    }
+
+    for (size_t index = 0; index < face_count; index++) {
+        const float *first = positions[faces[index][0]];
+        const float *second = positions[faces[index][1]];
+        const float *third = positions[faces[index][2]];
+        float edge_a[3] = {second[0] - first[0], second[1] - first[1], second[2] - first[2]};
+        float edge_b[3] = {third[0] - first[0], third[1] - first[1], third[2] - first[2]};
+        float face_normal[3] = {
+            edge_a[1] * edge_b[2] - edge_a[2] * edge_b[1],
+            edge_a[2] * edge_b[0] - edge_a[0] * edge_b[2],
+            edge_a[0] * edge_b[1] - edge_a[1] * edge_b[0],
+        };
+        for (int corner = 0; corner < 3; corner++) {
+            size_t position_index = faces[index][corner];
+            normal_accum[position_index * 3 + 0] += face_normal[0];
+            normal_accum[position_index * 3 + 1] += face_normal[1];
+            normal_accum[position_index * 3 + 2] += face_normal[2];
+        }
+    }
+
+    for (size_t index = 0; index < position_count; index++) {
+        float *normal = &normal_accum[index * 3];
+        float length = sqrtf(normal[0] * normal[0] + normal[1] * normal[1] + normal[2] * normal[2]);
+        if (length > 0.0f) {
+            normal[0] /= length;
+            normal[1] /= length;
+            normal[2] /= length;
+        } else {
+            normal[0] = 0.0f;
+            normal[1] = 0.0f;
+            normal[2] = 1.0f;
+        }
+    }
+
+    for (size_t index = 0; index < face_count; index++) {
+        for (int corner = 0; corner < 3; corner++) {
+            size_t position_index = faces[index][corner];
+            ta_model_vertex vertex;
+            memcpy(vertex.position, positions[position_index], sizeof(vertex.position));
+            memcpy(vertex.normal, &normal_accum[position_index * 3], sizeof(vertex.normal));
+            if (!ta_model_push_vertex(mesh, &vertex_capacity, &vertex)) {
+                goto done;
+            }
+        }
+    }
+
+    success = mesh->vertex_count > 0;
+done:
+    if (!success) {
+        ta_model_free(mesh);
+    }
+    free(normal_accum);
+    return success;
+}
+
+void ta_model_free(ta_model_mesh *mesh) {
+    free(mesh->vertices);
+    mesh->vertices = NULL;
+    mesh->vertex_count = 0;
+}
+
+typedef struct ta_model_uniforms {
+    float mvp[16];
+    float model[16];
+    float camera_position[3];
+    float padding;
+} ta_model_uniforms;
+
+static SDL_GPUShader *ta_model_shader(SDL_GPUDevice *device, const void *code, size_t size, SDL_GPUShaderStage stage) {
+    SDL_GPUShaderCreateInfo info = {
+        .code = code,
+        .code_size = size,
+        .entrypoint = "main",
+        .format = SDL_GPU_SHADERFORMAT_SPIRV,
+        .stage = stage,
+        .num_uniform_buffers = stage == SDL_GPU_SHADERSTAGE_VERTEX ? 1 : 0,
+    };
+    return ta_sdl_create_gpu_shader(device, &info);
+}
+
+static void ta_model_identity(float *matrix) {
+    for (int index = 0; index < 16; index++) matrix[index] = index % 5 == 0 ? 1.0f : 0.0f;
+}
+
+static void ta_model_multiply(float *result, const float *left, const float *right) {
+    float product[16];
+    for (int column = 0; column < 4; column++) for (int row = 0; row < 4; row++) {
+        product[column * 4 + row] = 0.0f;
+        for (int inner = 0; inner < 4; inner++) product[column * 4 + row] += left[inner * 4 + row] * right[column * 4 + inner];
+    }
+    memcpy(result, product, sizeof(product));
+}
+
+bool ta_model_init(ta_model *model, SDL_GPUDevice *device,
+                        const float positions[][3], size_t position_count,
+                        const unsigned int faces[][3], size_t face_count,
+                        SDL_GPUTextureFormat color_format, SDL_GPUTextureFormat depth_format, SDL_GPUSampleCount sample_count) {
+    memset(model, 0, sizeof(*model));
+    if (!ta_model_build(positions, position_count, faces, face_count, &model->mesh) || model->mesh.vertex_count == 0) return false;
+    float minimum[3];
+    float maximum[3];
+    memcpy(minimum, model->mesh.vertices[0].position, sizeof(minimum));
+    memcpy(maximum, minimum, sizeof(maximum));
+    for (size_t index = 1; index < model->mesh.vertex_count; index++) for (int axis = 0; axis < 3; axis++) {
+        if (model->mesh.vertices[index].position[axis] < minimum[axis]) minimum[axis] = model->mesh.vertices[index].position[axis];
+        if (model->mesh.vertices[index].position[axis] > maximum[axis]) maximum[axis] = model->mesh.vertices[index].position[axis];
+    }
+    float center[3] = {(minimum[0] + maximum[0]) * 0.5f, (minimum[1] + maximum[1]) * 0.5f, (minimum[2] + maximum[2]) * 0.5f};
+    float extent = maximum[0] - minimum[0];
+    for (int axis = 1; axis < 3; axis++) if (maximum[axis] - minimum[axis] > extent) extent = maximum[axis] - minimum[axis];
+    for (size_t index = 0; index < model->mesh.vertex_count; index++) for (int axis = 0; axis < 3; axis++) model->mesh.vertices[index].position[axis] = (model->mesh.vertices[index].position[axis] - center[axis]) * (2.2f / extent);
+
+    SDL_GPUBufferCreateInfo buffer_info = {.usage = SDL_GPU_BUFFERUSAGE_VERTEX, .size = (Uint32)(model->mesh.vertex_count * sizeof(*model->mesh.vertices))};
+    model->vertex_buffer = SDL_CreateGPUBuffer(device, &buffer_info);
+    if (!model->vertex_buffer) {
+        ta_model_free(&model->mesh);
+        return false;
+    }
+    model->vertex_count = (Uint32)model->mesh.vertex_count;
+    SDL_GPUShader *vertex_shader = ta_model_shader(device, file_obj_vert_slang_spv_start, file_obj_vert_slang_spv_size, SDL_GPU_SHADERSTAGE_VERTEX);
+    SDL_GPUShader *fragment_shader = ta_model_shader(device, file_obj_frag_slang_spv_start, file_obj_frag_slang_spv_size, SDL_GPU_SHADERSTAGE_FRAGMENT);
+    SDL_GPUVertexBufferDescription vertex_buffer = {.slot = 0, .pitch = sizeof(ta_model_vertex), .input_rate = SDL_GPU_VERTEXINPUTRATE_VERTEX};
+    SDL_GPUVertexAttribute attributes[2] = {
+        {.location = 0, .buffer_slot = 0, .format = SDL_GPU_VERTEXELEMENTFORMAT_FLOAT3, .offset = 0},
+        {.location = 1, .buffer_slot = 0, .format = SDL_GPU_VERTEXELEMENTFORMAT_FLOAT3, .offset = sizeof(float) * 3},
+    };
+    SDL_GPUColorTargetDescription color_target = {.format = color_format};
+    SDL_GPUGraphicsPipelineCreateInfo pipeline_info = {
+        .vertex_shader = vertex_shader,
+        .fragment_shader = fragment_shader,
+        .vertex_input_state = {.vertex_buffer_descriptions = &vertex_buffer, .num_vertex_buffers = 1, .vertex_attributes = attributes, .num_vertex_attributes = 2},
+        .primitive_type = SDL_GPU_PRIMITIVETYPE_TRIANGLELIST,
+        .rasterizer_state = {.cull_mode = SDL_GPU_CULLMODE_NONE},
+        .depth_stencil_state = {.compare_op = SDL_GPU_COMPAREOP_LESS, .enable_depth_test = true, .enable_depth_write = true},
+        .multisample_state = {.sample_count = sample_count},
+        .target_info = {.num_color_targets = 1, .color_target_descriptions = &color_target, .depth_stencil_format = depth_format, .has_depth_stencil_target = true},
+    };
+    model->pipeline = ta_sdl_create_gpu_graphics_pipeline(device, &pipeline_info);
+    SDL_ReleaseGPUShader(device, vertex_shader);
+    SDL_ReleaseGPUShader(device, fragment_shader);
+    return model->pipeline != NULL;
+}
+
+void ta_model_upload(ta_model *model, SDL_GPUCommandBuffer *command_buffer, SDL_GPUDevice *device) {
+    if (model->uploaded || !model->vertex_buffer) return;
+    Uint32 size = (Uint32)(model->mesh.vertex_count * sizeof(*model->mesh.vertices));
+    SDL_GPUTransferBufferCreateInfo transfer_info = {.usage = SDL_GPU_TRANSFERBUFFERUSAGE_UPLOAD, .size = size};
+    SDL_GPUTransferBuffer *transfer_buffer = ta_sdl_create_gpu_transfer_buffer(device, &transfer_info);
+    void *mapped = ta_sdl_map_gpu_transfer_buffer(device, transfer_buffer, false);
+    memcpy(mapped, model->mesh.vertices, size);
+    SDL_UnmapGPUTransferBuffer(device, transfer_buffer);
+    SDL_GPUCopyPass *copy_pass = ta_sdl_begin_gpu_copy_pass(command_buffer);
+    SDL_GPUTransferBufferLocation source = {.transfer_buffer = transfer_buffer};
+    SDL_GPUBufferRegion destination = {.buffer = model->vertex_buffer, .size = size};
+    SDL_UploadToGPUBuffer(copy_pass, &source, &destination, false);
+    SDL_EndGPUCopyPass(copy_pass);
+    SDL_ReleaseGPUTransferBuffer(device, transfer_buffer);
+    ta_model_free(&model->mesh);
+    model->uploaded = true;
+}
+
+void ta_model_render(const ta_model *model, SDL_GPUCommandBuffer *command_buffer, SDL_GPURenderPass *render_pass, int window_width, int window_height) {
+    if (!model->pipeline || !model->vertex_buffer || !model->uploaded) return;
+    ta_model_uniforms uniforms;
+    float view[16];
+    float projection[16] = {0};
+    float view_model[16];
+    float rotation_x[16];
+    float rotation_y[16];
+    float rotation_z[16];
+    float rotation_xy[16];
+    float cosine = cosf(model->rotation[0]);
+    float sine = sinf(model->rotation[0]);
+    ta_model_identity(rotation_x);
+    rotation_x[5] = cosine;
+    rotation_x[6] = sine;
+    rotation_x[9] = -sine;
+    rotation_x[10] = cosine;
+    cosine = cosf(model->rotation[1]);
+    sine = sinf(model->rotation[1]);
+    ta_model_identity(rotation_y);
+    rotation_y[0] = cosine;
+    rotation_y[2] = -sine;
+    rotation_y[8] = sine;
+    rotation_y[10] = cosine;
+    cosine = cosf(model->rotation[2]);
+    sine = sinf(model->rotation[2]);
+    ta_model_identity(rotation_z);
+    rotation_z[0] = cosine;
+    rotation_z[1] = sine;
+    rotation_z[4] = -sine;
+    rotation_z[5] = cosine;
+    ta_model_multiply(rotation_xy, rotation_y, rotation_x);
+    ta_model_multiply(uniforms.model, rotation_z, rotation_xy);
+    uniforms.model[12] = model->position[0];
+    uniforms.model[13] = model->position[1];
+    uniforms.model[14] = model->position[2];
+    float aspect = (float)window_width / (float)window_height;
+    float focal_length = 1.0f / tanf(22.5f * 0.01745329252f);
+    float near_plane = 0.1f;
+    float far_plane = 100.0f;
+    ta_camera_get_view_matrix(view);
+    projection[0] = focal_length / aspect;
+    projection[5] = focal_length;
+    projection[10] = far_plane / (near_plane - far_plane);
+    projection[11] = -1.0f;
+    projection[14] = near_plane * far_plane / (near_plane - far_plane);
+    ta_model_multiply(view_model, view, uniforms.model);
+    ta_model_multiply(uniforms.mvp, projection, view_model);
+    uniforms.camera_position[0] = ta_camera_current.x;
+    uniforms.camera_position[1] = ta_camera_current.y;
+    uniforms.camera_position[2] = ta_camera_current.z;
+    uniforms.padding = 0.0f;
+    SDL_PushGPUVertexUniformData(command_buffer, 0, &uniforms, sizeof(uniforms));
+    SDL_BindGPUGraphicsPipeline(render_pass, model->pipeline);
+    SDL_GPUBufferBinding binding = {.buffer = model->vertex_buffer};
+    SDL_BindGPUVertexBuffers(render_pass, 0, &binding, 1);
+    SDL_DrawGPUPrimitives(render_pass, model->vertex_count, 1, 0, 0);
+}
+
+void ta_model_destroy(ta_model *model, SDL_GPUDevice *device) {
+    SDL_ReleaseGPUGraphicsPipeline(device, model->pipeline);
+    SDL_ReleaseGPUBuffer(device, model->vertex_buffer);
+    ta_model_free(&model->mesh);
+    memset(model, 0, sizeof(*model));
+}
\ No newline at end of file